mnemonicPrefix = true in gitconfig breaks hunk staging

[bo5o]

Describe the bug

Setting mnemonicPrefix = true under [diff] in gitconfig breaks staging hunks in the latest lazygit. Pressing space in the focused diff shows "Apply Patch" in the command log, but nothing gets staged. Discarding and unstaging are affected the same way.

To Reproduce

Steps to reproduce the behavior:

1. git config --global diff.mnemonicPrefix true
2. Modify a tracked file in any repo
3. In lazygit, select the file in the Files panel and press enter to focus its diff
4. Press space on a hunk or line
5. "Apply Patch" appears in the command log, but the change stays unstaged (git status confirms)

Expected behavior

The selected hunk or line is staged, the same as without diff.mnemonicPrefix.

Screenshots

n/a

Version info:

commit=c5f7158154602d23b0750d4304c73e2aead8df5b, build date=2026-10-05T17:12:24Z, build source=binaryRelease, version=0.66.0, os=linux, arch=amd64, git version=2.55.0

Terminal info:

Ghostty 1.3.1

Additional Context

None

[stefanhaller]

@bo5o Thanks for reporting; fixed in #6099. I added a second PR that makes lazygit show an error popup in such a case rather than silently doing nothing (#6100); the second PR is stacked on the first, so if you want to test the fix (which I would appreciate), please use a build of #6100.

[arlopezg]

I noticed the same issue yesterday after updating, but couldn't quite describe what was wrong (or what caused it). I built #6100 locally just now and can confirm it seems to be fixed.

v0.66	dev
2026-10-07_21-27-13.mp4	2026-10-07_21-28-06.mp4

(env: Arch with mnemonicPrefix=true)